Modern CFLs of reputable make should not flicker, though some cheap ones do.
Daylight CFLs are often prefered for reading or close work.
The claimed light output is often a bit optimistic, and I would choose a CFL with a wattage of 25% of the incandescent lamp it is to replace.
For example I would replace a 60 watt incandescent with a 15 watt CFL not with an 11 watt.
I would avoid so called low energy halogen lamps, they are only slightly more efficient than regular halogen lamps, and far behind CFLs.